Field of the Invention
The present invention relates to a retractable lens apparatus to be used for image capturing apparatuses such as digital cameras and video cameras.
Description of the Related Art
Compact image capturing apparatuses are often provided with a retractable lens barrel (lens apparatus) whose barrel length becomes long by an object-side protrusion of a movable barrel with respect to a base barrel in an image capturing state, and becomes short by retraction of the movable barrel with respect to the base barrel in a non-image capturing state. In order to ensure a relative positional accuracy between the base barrel and the movable barrel for satisfying a required optical performance in the image capturing state, the retractable lens barrel needs to have a reduced relative eccentricity and a reduced relative tilt between the base barrel and the movable barrel.
Japanese patent Laid-Open No. 2010-266582 discloses a lens barrel in which a lens holding member (lens holder) holding a lens is biased with a spring so that a relative eccentricity and a relative tilt between multiple lenses are reduced. Specifically, the lens holder guided by a guide shaft is biased with the spring so as to be in contact with the guide shaft with pressure, and thereby an eccentricity of the lens holder in a plane orthogonal to an optical axis and a tilt of the lens holder with respect to the optical axis are reduced.
On other hand, image capturing apparatuses that can perform moving image capturing need to move a lens quietly for preventing noise from being recorded and to move the lens smoothly for preventing image shaking during the moving image capturing. Therefore, these image capturing apparatuses often employ a lens driving mechanism to move a lens holder by using a lead screw or the like with guide of the lens holder by a guide shaft. Such a configuration needs to detect the position of the lens holder in order to perform position control thereof and thus generally includes a position detector, such as a photo interrupter, to detect a reference position that is a position detection reference of the lens holder at one place in a movable range of the lens holder. Specifically, a detection operation of the reference position is performed by moving the lens holder near the position detector after power-on of the image capturing apparatus and before start of the image capturing.
However, there is the following problem in an image capturing apparatus provided with the above-mentioned retractable lens barrel and performing the eccentricity and tilt adjustments of the movable barrel or the lens holder, and an operation to detect the reference position of the lens holder. Such an image capturing apparatus enters into a standby state of allowing image capturing (image capturing standby state) after the power-on thereof. After power-on the lens barrel protrudes from its retracted state and then the eccentricity and tilt adjustments and the reference position detection operation are completed, before the image capturing standby state is entered. This sequence causes a problem that a standby wait time which is a period of time required from the power-on to the image capturing standby state becomes long.